1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/minix/namei.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  */
7 
8 #include "minix.h"
9 
add_nondir(struct dentry * dentry,struct inode * inode)10 static int add_nondir(struct dentry *dentry, struct inode *inode)
11 {
12 	int err = minix_add_link(dentry, inode);
13 	if (!err) {
14 		d_instantiate(dentry, inode);
15 		return 0;
16 	}
17 	inode_dec_link_count(inode);
18 	iput(inode);
19 	return err;
20 }
21 
minix_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)22 static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
23 {
24 	struct inode * inode = NULL;
25 	ino_t ino;
26 
27 	if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen)
28 		return ERR_PTR(-ENAMETOOLONG);
29 
30 	ino = minix_inode_by_name(dentry);
31 	if (ino)
32 		inode = minix_iget(dir->i_sb, ino);
33 	return d_splice_alias(inode, dentry);
34 }
35 
minix_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)36 static int minix_mknod(struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev)
37 {
38 	int error;
39 	struct inode *inode;
40 
41 	if (!old_valid_dev(rdev))
42 		return -EINVAL;
43 
44 	inode = minix_new_inode(dir, mode, &error);
45 
46 	if (inode) {
47 		minix_set_inode(inode, rdev);
48 		mark_inode_dirty(inode);
49 		error = add_nondir(dentry, inode);
50 	}
51 	return error;
52 }
53 
minix_tmpfile(struct inode * dir,struct dentry * dentry,umode_t mode)54 static int minix_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
55 {
56 	int error;
57 	struct inode *inode = minix_new_inode(dir, mode, &error);
58 	if (inode) {
59 		minix_set_inode(inode, 0);
60 		mark_inode_dirty(inode);
61 		d_tmpfile(dentry, inode);
62 	}
63 	return error;
64 }
65 
minix_create(struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)66 static int minix_create(struct inode *dir, struct dentry *dentry, umode_t mode,
67 		bool excl)
68 {
69 	return minix_mknod(dir, dentry, mode, 0);
70 }
71 
minix_symlink(struct inode * dir,struct dentry * dentry,const char * symname)72 static int minix_symlink(struct inode * dir, struct dentry *dentry,
73 	  const char * symname)
74 {
75 	int err = -ENAMETOOLONG;
76 	int i = strlen(symname)+1;
77 	struct inode * inode;
78 
79 	if (i > dir->i_sb->s_blocksize)
80 		goto out;
81 
82 	inode = minix_new_inode(dir, S_IFLNK | 0777, &err);
83 	if (!inode)
84 		goto out;
85 
86 	minix_set_inode(inode, 0);
87 	err = page_symlink(inode, symname, i);
88 	if (err)
89 		goto out_fail;
90 
91 	err = add_nondir(dentry, inode);
92 out:
93 	return err;
94 
95 out_fail:
96 	inode_dec_link_count(inode);
97 	iput(inode);
98 	goto out;
99 }
100 
minix_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)101 static int minix_link(struct dentry * old_dentry, struct inode * dir,
102 	struct dentry *dentry)
103 {
104 	struct inode *inode = d_inode(old_dentry);
105 
106 	inode->i_ctime = current_time(inode);
107 	inode_inc_link_count(inode);
108 	ihold(inode);
109 	return add_nondir(dentry, inode);
110 }
111 
minix_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)112 static int minix_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
113 {
114 	struct inode * inode;
115 	int err;
116 
117 	inode_inc_link_count(dir);
118 
119 	inode = minix_new_inode(dir, S_IFDIR | mode, &err);
120 	if (!inode)
121 		goto out_dir;
122 
123 	minix_set_inode(inode, 0);
124 
125 	inode_inc_link_count(inode);
126 
127 	err = minix_make_empty(inode, dir);
128 	if (err)
129 		goto out_fail;
130 
131 	err = minix_add_link(dentry, inode);
132 	if (err)
133 		goto out_fail;
134 
135 	d_instantiate(dentry, inode);
136 out:
137 	return err;
138 
139 out_fail:
140 	inode_dec_link_count(inode);
141 	inode_dec_link_count(inode);
142 	iput(inode);
143 out_dir:
144 	inode_dec_link_count(dir);
145 	goto out;
146 }
147 
minix_unlink(struct inode * dir,struct dentry * dentry)148 static int minix_unlink(struct inode * dir, struct dentry *dentry)
149 {
150 	int err = -ENOENT;
151 	struct inode * inode = d_inode(dentry);
152 	struct page * page;
153 	struct minix_dir_entry * de;
154 
155 	de = minix_find_entry(dentry, &page);
156 	if (!de)
157 		goto end_unlink;
158 
159 	err = minix_delete_entry(de, page);
160 	if (err)
161 		goto end_unlink;
162 
163 	inode->i_ctime = dir->i_ctime;
164 	inode_dec_link_count(inode);
165 end_unlink:
166 	return err;
167 }
168 
minix_rmdir(struct inode * dir,struct dentry * dentry)169 static int minix_rmdir(struct inode * dir, struct dentry *dentry)
170 {
171 	struct inode * inode = d_inode(dentry);
172 	int err = -ENOTEMPTY;
173 
174 	if (minix_empty_dir(inode)) {
175 		err = minix_unlink(dir, dentry);
176 		if (!err) {
177 			inode_dec_link_count(dir);
178 			inode_dec_link_count(inode);
179 		}
180 	}
181 	return err;
182 }
183 
minix_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)184 static int minix_rename(struct inode * old_dir, struct dentry *old_dentry,
185 			struct inode * new_dir, struct dentry *new_dentry,
186 			unsigned int flags)
187 {
188 	struct inode * old_inode = d_inode(old_dentry);
189 	struct inode * new_inode = d_inode(new_dentry);
190 	struct page * dir_page = NULL;
191 	struct minix_dir_entry * dir_de = NULL;
192 	struct page * old_page;
193 	struct minix_dir_entry * old_de;
194 	int err = -ENOENT;
195 
196 	if (flags & ~RENAME_NOREPLACE)
197 		return -EINVAL;
198 
199 	old_de = minix_find_entry(old_dentry, &old_page);
200 	if (!old_de)
201 		goto out;
202 
203 	if (S_ISDIR(old_inode->i_mode)) {
204 		err = -EIO;
205 		dir_de = minix_dotdot(old_inode, &dir_page);
206 		if (!dir_de)
207 			goto out_old;
208 	}
209 
210 	if (new_inode) {
211 		struct page * new_page;
212 		struct minix_dir_entry * new_de;
213 
214 		err = -ENOTEMPTY;
215 		if (dir_de && !minix_empty_dir(new_inode))
216 			goto out_dir;
217 
218 		err = -ENOENT;
219 		new_de = minix_find_entry(new_dentry, &new_page);
220 		if (!new_de)
221 			goto out_dir;
222 		minix_set_link(new_de, new_page, old_inode);
223 		new_inode->i_ctime = current_time(new_inode);
224 		if (dir_de)
225 			drop_nlink(new_inode);
226 		inode_dec_link_count(new_inode);
227 	} else {
228 		err = minix_add_link(new_dentry, old_inode);
229 		if (err)
230 			goto out_dir;
231 		if (dir_de)
232 			inode_inc_link_count(new_dir);
233 	}
234 
235 	minix_delete_entry(old_de, old_page);
236 	mark_inode_dirty(old_inode);
237 
238 	if (dir_de) {
239 		minix_set_link(dir_de, dir_page, new_dir);
240 		inode_dec_link_count(old_dir);
241 	}
242 	return 0;
243 
244 out_dir:
245 	if (dir_de) {
246 		kunmap(dir_page);
247 		put_page(dir_page);
248 	}
249 out_old:
250 	kunmap(old_page);
251 	put_page(old_page);
252 out:
253 	return err;
254 }
255 
256 /*
257  * directories can handle most operations...
258  */
259 const struct inode_operations minix_dir_inode_operations = {
260 	.create		= minix_create,
261 	.lookup		= minix_lookup,
262 	.link		= minix_link,
263 	.unlink		= minix_unlink,
264 	.symlink	= minix_symlink,
265 	.mkdir		= minix_mkdir,
266 	.rmdir		= minix_rmdir,
267 	.mknod		= minix_mknod,
268 	.rename		= minix_rename,
269 	.getattr	= minix_getattr,
270 	.tmpfile	= minix_tmpfile,
271 };
272